The Maine Supreme Judicial Court has upheld a trial court's dismissal of invasion of privacy claims against a defendant who surreptitiously filmed encounters between prostitutes and their customers. In State v. Strong, the Court wrote in part,

When first enacted in 1976, section 511 defined a "private place" to mean "a place where one may reasonably expect to be safe from surveillance but does not include a place to which the public or a substantial group has access." P.L. 1975, ch. 499, § 1. The comment immediately following the text of the bill as enacted states that the provision was intended "to prevent [the] seeing or hearing of things that are justifiably expected to be kept private." ... Through amendments in 1999 and 2008, the Legislature revised the definition of "private place" by removing the language excluding "a place to which the public or a substantial group has access" and adding the language, "including, but not limited to, changing or dressing rooms, bathrooms and similar places." See P.L. 2007, ch. 688, § 2; P.L. 1999, ch. 116, § 1.

... Thus, the Legislature's overall purpose in criminalizing certain violations of privacy cannot be understood as an effort to broadly protect individuals' subjective expectations of privacy. The purpose is more focused, requiring that certain objective factors be present as well. The place involved must be "a place where one may reasonably expect to be safe from surveillance." ... Further, a person's desire to keep private what transpires within that place must be a justifiable expectation, and, therefore, objectively reasonable. ...

Applying these standards to the unique facts delimited by the counts of the indictment as augmented by the State's offer of proof, the persons who entered and disrobed in the places described in the offer of proof—a residence, studio, and business office where a prostitute conducted her business—may have held a subjective expectation of privacy. Nevertheless, they cannot qualify as "persons entitled to privacy" in those places for purposes of the objective requirements of section 511(1)(B) because, as established by the State's offer of proof, their sole purpose for being present in those places was to engage a prostitute. Places of prostitution and people who knowingly frequent them to engage a prostitute are not sanctioned by society. Accordingly, it is objectively unreasonable for a person who knowingly enters a place of prostitution for the purpose of engaging a prostitute to expect that society recognizes a right to be safe from surveillance while inside.